How can I automatically have my Trash emptied when disk space gets below a certain point?

Question

Sometimes my hard drive gets low on space, and various things don't work properly until I empty the Trash and free up some space. I know there are applications that empty the Trash after a set interval—but what I want is an app or script (or other means) to empty the Trash whenever there's e.g. less than 2GB of free space on a given hard drive.

Answer 1

I use a third party preference pane Compost that deletes from trash when the disk fills up or if the file has been in trash for a given time.

The original download stopped working for me but I have just found this on the author's site instead of the distributer. Note the author's comment

Compost is in a bit of a state of flux right now. The distributor has moved on to a different market and we wish them well in their endeavors. Additionally, the changes necessary to fully support Snow Leopard have been going through an extensive beta period as a result of the degree and complexity of changes required. Please stay tuned for more information.

So it might not work even from this download

When I updated this I had just installed it on Yosemite and it installed (but not enough time to see if it deleted anything) I have now updated to El Capitan and the installer fails.

Answer 2

You could also edit the crontab with EDITOR=nano crontab -e and add a line like

0 * * * * osascript -e 'tell app "Finder" to empty trash if free space of startup disk < 2.0E+9'

Hazel supports keeping the trash under a certain size or keeping items only for a period like two weeks.

Answer 3

I use CleanMyMac, though there are lots of others that do a similar job. CleanMyMac also cleans cache, etc. Hazel is also good for cleaning out folders that fill up with rubbish quite frequently.

Answer 4

That's an interesting question.

I wrote a little shell script that will empty the trash if the available disk space falls before a threshold defined in the script (default is 10 GB but you can change that by editing the script).

Install script

1. Download this: http://share.luo.ma/ase/12167/etilds.zsh

2. Install it to /usr/local/bin/etilds.zsh

3. Then do chmod 755 /usr/local/bin/etilds.zsh

Use launchd for automatic trash emptying

If you want this to run automatically, I recommend launchd. To do that

1. Download this http://share.luo.ma/ase/12167/com.tjluoma.etilds.plist

2. Move it to ~/Library/LaunchAgents/

3. Tell it to run via launchctl load ~/Library/LaunchAgents/com.tjluoma.etilds.plist

It will run every 5 minutes (300 seconds) by default. You can edit that too.

To uninstall:

delete /usr/local/bin/etilds.zsh and ~/Library/LaunchAgents/com.tjluoma.etilds.plist and reboot.

Notes and Disclaimer

• No guarantees or warranty but it works for me. Use at your own risk.

• You have to edit etilds.zsh. Read it and you'll understand what to do.

• "etilds" stands for "Empty Trash If Low Disk Space" because a) I couldn't come up with a better name and b) it seemed a sufficiently unix-y acronym.